Create maximum-alternating-subarray-sum.py

Author: kamyu104

Python/maximum-alternating-subarray-sum.py

@@ -0,0 +1,19 @@
+# Time:  O(n)
+# Space: O(1)
+
+class Solution(object):
+    def maximumAlternatingSubarraySum(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        def kadane(nums, start):
+            result = float("-inf")
+            curr = odd = 0
+            for i in xrange(start, len(nums)):
+                curr = (curr+nums[i]) if not odd else max(curr-nums[i], 0)
+                result = max(result, curr)
+                odd ^= 1
+            return result
+
+        return max(kadane(nums, 0), kadane(nums, 1))